The present invention relates generally to an active clutch device utilized on a stabilizer bar of a vehicle suspension system which includes a plurality of interacting dampers which provide variable stiffness in the stabilizer bar.
Vehicles are commonly equipped with suspension systems for absorbing road shock and other vibrations, while providing for a smooth and comfortable ride. Also tipping or rolling over of vehicles is undesirable. A suspension component, such as a stabilizer bar, is often used to increase roll rigidity and improve the steering stability of the vehicle. The stabilizer bar is generally attached to the lower A-arms of the suspension system and controls sway as the vehicle turns and provides a pull down force during cornering.
As a vehicle turns, the body of the vehicle rolls to the outside of the turn. The suspension components on the outside of the turn are generally compressed, while the suspension components on the inside of the turn are generally extended. The stabilizer bar counters this motion by pushing up on the suspension components collapsed through torsion in the stabilizer bar.
During cornering, it is desirable that the stiffness of the stabilizer bar be increased. If the stabilizer bar is too compliant, the vehicle will not respond well during cornering, increasing the likelihood of rolling over. However, if the stabilizer is too stiff, the ride and handling will be compromised during normal vehicle operation. Therefore, it is desirable that the compliance of the stabilizer bar be variable to adjust for changing driving conditions.
In a proposed vehicle suspension system, a clutch device includes a chamber which houses a plurality of discs and either a magnetic-rheological or electro-rheological fluid. On the application of either a high strength magnetic or electrical field, respectively, the fluid increases in viscosity, which increases both the stiffness of the stabilizer bar and the ride of the vehicle. In this system, the discs are attached to a pair of split stabilizer bars, the discs selectively driving each other.
This invention relates to an active clutch device for use on a stabilizer bar of a vehicle suspension system to provide variable stiffness in the stabilizer bar.
A clutch device positioned in the middle of a split stabilizer bar is employed to vary the stabilizer bar stiffness. A clutch body secured to the vehicle frame includes a plurality of clutch dampers which alternate with a plurality of bar dampers which are secured to the stabilizer bar. The alternating dampers are coated with a friction material and surrounded with a fluid enclosed in the clutch body by walls. When a load is applied on the walls, the walls pressing the friction material together to dampen the rotational action of the stabilizer bar. The walls are secured to the clutch body and the stabilizer bar by a sliding component, such as an annular elastic bead, which allows for the slight movement of the walls.
A sensor senses the ride parameters and generates a signal based on these parameters. When the vehicle corners and the sensor detects a need for an increase in vehicle roll stiffness, the sensor generates a signal which activates a power source controller. The controller proportionally applies the load to the walls, proportionally dampening the stabilizer bar. The load can be applied from a hydraulic, pneumatic, or electrical power source. Alternatively, the load can be applied by applying a magnetic or electrical field to magnetic-rheological or electro-rheological fluid, respectively, in the clutch body.
Accordingly, the present invention provides an active clutch device for use on a stabilizer bar of a vehicle suspension system to provide variable stiffness in the stabilizer bar.
These and other features of the present invention will be best understood from the following specification and drawings.